Forms A Tight Barrier Against Fire, Smoke And Toxic Fumes. Suitable For A Wide Variety Of Through-Penetration Fire Stops, Including Cable, Metal Pipe, Insulated Pipe, Glass Pipe, Construction Gaps, HVAC Ductwork And Certain Plastic Pipe Applications. Cures To Form A Flexible Seal, Installs With A Standard Caulking Gun, Pneumatic Pumping Equipment Or Putty Knife. ASTM, FM And U.L. Tested For 3 Hour Fire Penetration Seal For Walls And Floors.